I'm not exactly against the idea of a reboot... It's just that what made Buffy work was more then just a girl slaying vampires and being "witty, tough and sexy". There was some actually decent characterisation and development that went along with all that. Not to mention that one of the most enjoyable aspects of the show was the scoobie gang (Giles included).
I have this cynical feeling that the only reason it's being made is to cash in on the slew of Vampire related shows/movies.
I won't say it'll be terrible, but to be honest I can't see it being all that good.